Process of preparing a printing plate for accurate registration

ABSTRACT

The invention disclosed is a method for preparing a printing plate for accurate registration onto a press. Registration areas are first provided in proper alignment relative to the printing area of the plate being processed. Next, means are provided for positioning the registration areas in fixed location for shearing of the plate along the width and length edges thereof. Shearing of the length, along opposite ends of the plate, is accompanied by punching saddle engaging slots, and binding. The plate so processed is ready for accurate introduction directly onto a printing press where the ends are conveniently secured in place about a saddle.

United States Patent Eburn, jr.

[ Nov. 13, 1973 PROCESS OF PREPARING A PRINTING PLATE FOR ACCURATE REGISTRATION Appl. No.: 230,249

US. Cl '101/1, 29/34, 72/294,

101/DlG. 12, 101/4151 [51] Int. Cl B21d 43/28, B41f 27/06 [58] Field of Search 101/DIG. 12, 415.1, 101/1; 29/34; 72/294, 306

[56] References Cited UNITED STATES PATENTS 1,461,068 7/1923 Regensteiner 101/415.l 2,460,483 2/1949 Berliner 72/294 2,579,753 12/1951 Norquist 72/294 2,963,066 12/1960 Nelson 72/294 2,680,405 6/1954 Faeber et a1... lOl/DIG. 12 2,785,630 3/1957 LeGate lOl/DIG. 12 2,786,385 3/1957 Satre et al lOl/DlG. 12 3,288,063 11/1966 Bungay lOl/DIG. 12

2,234,170 3/1941 Huck 101/DlG. 12 2,192,924 3/1940 Maher et a1. 12 2,659,282 11/1953 Freund 12 2,668,363 2/1954 Lippitt lOl/DlG. 12

Primary Examiner-Clyde I. Coughenour Att0rney-Eugene M. Bond ABSTRACT plate, is accompanied by punching saddle engaging slots, and binding. The plate so processed is ready for accurate introduction directly onto a printing press where the ends are conveniently secured in place about a saddle.

1 Claim, 6 Drawing Figures PATENIEUMIV 13 ms SHEET 18F 2 Www PROCESS OF PREPARING A PRINTING PLATE FOR ACCURATE REGISTRATION This invention relates to a method for preparing a printing plate for accurate press registration. More particularly, the present invention provides a method for preparing a printing plate for direct introduction onto a press saddle by accurately shearing the edges thereof while punching saddle engaging slots along opposite bended ends of the plate.

It is known that printing plates may be prepared using photocurable compositions. One example of such a method is that described in US. Pat. No. 3,615,450. In preparing such plates especially when using a thin metal support plate such as of aluminum, steel or the like, it becomes necessary to accurately align the printing area relative to the saddle engaging areas prior to introduction onto a printing press. The present invention provides a method which prepares flexible thin printing plates, especially those witha thin metal support backing, for direct introduction, accurately aligned onto a printing press saddle.

When a printing plate is prepared by exposing a photocurable composition through a transparency, registration areas are provided in non-printing areas of the transparency such that upon exposure the registration areas become part of the non-printing photocured areas of the printing plate being processed. These registration areas are carefully aligned with the printing area and, as will be subsequently apparent, they eliminate great concern for alignment of the saddle engaging areas of the metal backing at the time of exposure.

Having so prepared a printing plate, the finally developed plate is ready for further processing steps of shearing, punching, and bending.

Generally stated, the present method includes the steps of providing registration areas on a transparency such that registration areas accurately aligned relative to the printing area will appear on a metal backed printing plate by way of exposure, positioning the printing plate with registration areas after development in a fixed location, shearing the plate along a width measurement thereof, shearing the plate and punching saddle engaging slots along opposite ends of a length measurement thereof, and bending edges having the saddle engaging slots. In an embodiment of the present invention, bending is accompanied by stretching in the length direction to insure against spring return of the bended edges to original position.

Practice of the present invention will become more apparent from the following detailed descriptions taken in connection with the accompanying drawings wherein like numerals refer to similar elements throughout the several views.

FIG. 1 diagrammatically illustrates, as a perspective view, exposing through a transparency to effect positioning of registration areas;

FIG. 2 shows a side elevational view in partial section illustrating the positioning of registration areas in fixed location;

FIG. 3 similarly taken to FIG. 2, illustrates shearing along the length of the plate;

FIG. 4 is a side elevation view in partial section taken 90 removed to that of FIG. 2, and illustrates shearing of edges and punching of saddle engaging slots along opposite ends of the plate;

FIG. 5 similarly taken to FIG. 4 illustrates bending of the opposite ends of the plate which may be followed, if desired, by the step of FIG. 4; and

FIG. 6 is a perspective top view of the finally processed plate ready for mounting onto the saddle of a printing press.

Referring to the drawings, the present invention initially involves providing registration areas aligned relative to the printing plate area. In FIG. 1, printing plate 10 is illustrated having a metal backing 12, a photocurable polymer 14 with printing area 16, and registration areas 18 formed thereon. The printing area and registration areas result by exposing transparency film 20 having printing areas 22 and registration areas 24 thereon, using a light source 26 for exposure such as ultra-violet light.

After exposure of the plate has been effected, with subsequent processing as may be necessary for development, printing plate 10 is then processed at the step of FIG. 2. The printing plate 10 having metal backing 12 is placed on vacuum table 30 or other convenient support whereon it is aligned using aligning means 28 which cooperate with registration areas 18. The printing plate is held in fixed position by a suitable means such as by vacuum ports 32 receiving vacuum from a convenient source by line 34. It is recognized that other means may be used to secure the plate in fixed position provided that such means does not interfere with subsequent processing steps hereof and also that damage of the printing surface does not result.

After the printing plate has been registered and fixed in position such as that illustrated in FIG. 2, the plate is sheared along the width thereof. Thus, because of the registration areas and by fixing the plate in position, accurate shearing of the width edges relative the printing area is accomplished. Shearing of the width edges may be accomplished by shearing means 36 either prior to or subsequent to shearing of the ends of the plate, as desired.

The ends of the plate are sheared, punched, and bent, in sequence as desired, such as illustrated in FIGS. 4 and 5. With plate 10 in fixed position shearing means 38 engages the plate for accurately shearing the end edges of the plate relative to the printing areas. Punching of saddle engaging slots may be accomplished by punch 40 illustrated as a component of shearing means 38.

In order to avoid movement of plate 10 from fixed position, the sequence of end shearing, punching and bending is accomplished without release of the plate either during or between each processing step. Thus, once the ends of the plate are engaged for end processing, the sequence of shearing, punching and bending with optional bend stretching is accomplished before the plate is released.

In FIGS. 4 and 5, ends of metal backing 12 of printing plate 10 in fixed position over vacuum table 30, are engaged by shearing means 38 and punch 40. Shearing means 38 and punch 40 are disposed such that they may rotate as indicated by arrow 41 to effect bending, and further being disposed such that they may stretch the plate during bending in the direction of arrow 42. Stretching is optionally desired in instances when metal backings are characterized such that bends have a spring tendency to return to normal flat position, i.e., spring type steel or the like. In such instances, stretching during bending has a tendency to insure retention of the bend. After bending has been accomplished, the end processing means release the plate which is now ready for introduction onto a saddle.

After the sequence of FIGS. 4 and 5, the means used to retain the plate in fixed position, such as vacuum table 30, is replaced thus providing a printing plate such as that illustrated in FIG. 6.

FIG. 6 illustrates finally processed printing plate 44 having accurately positioned edges 46 bended for mounting by way of slots 48 onto the saddle of a printing press.

Although the present method has been described for convenience with regard to photocuring techniques, it will be apparent that it is readily applicable to other printing plate processing techniques such as photoengraving, thermal engraving, and direct etching.

The printing plates formed by the process of the instant invention may be employed in various types of printing including but not limited to intaglio printing, flexographic printing, letterpress printing, dry offset printing, and the like.

Although a preferred embodiment of the invention has been illustrated herein, it is to be understood that various changes and modifications may be made in the construction and arrangement of elements without departing from the spirit and scope of the invention as defined.

What is claimed is:

1. A method for preparing-a printing plate for accurate registration onto a press, said method consisting essentially of providing registration areas in nonprinting portions of a printing plate having a thin metal support layer, positioning the printing plate using the registration areas in fixed location and maintaining the plate in fixed position while shearing the plate along a width measurement thereof, shearing the plate and punching saddle engaging slots along opposite ends of a length measurement thereof, and bending edges while simultaneously punching saddle engaging slots, said bending and punching being accompanied by simultaneous stretching in the length direction to insure against spring return of the bended edges to original position. 

1. A method for preparing a printing plate for accurate registration onto a press, said method consisting essentially of providing registration areas in non-printing portions of a printing plate having a thin metal support layer, positioning the printing plate using the registration areas in fixed location and maintaining the plate in fixed position while shearing the plate along a width measurement thereof, shearing the plate and punching saddle engaging slots along opposite ends of a length measurement thereof, and bending edges while simultaneously punching saddle engaging slots, said bending and punching being accompanied by simultaneous stretching in the length direction to insure against spring return of the bended edges to original position. 